1. Field of the Invention
The present invention relates to an optometer for performing a refraction measurement of eyes to be examined, and more particularly to a technology for automatically inputting characters and symbols, which represent measurement values of a refractive power, an inter-pupil distance, and the like displayed on the optometer.
2. Description of the Related Art
In recent years, networking and automation of an optometer for use in an eyeglass shop have been progressing. However, for a phoropter, a trial frame, and the like, manual types, that is, manually operated types have been mainstreams because of merits in terms of operability, cost, and the like (for example, refer to JP 2002-315723 A, Paragraph Nos. 0007 and 0008 in Specification, and FIG. 1).
FIG. 11 shows an example of a conventional optometer. An optometer 100 shown in the drawing is a system for performing a subjective measurement of eyes to be examined. The optometer 100 has a structure including a manual-type subjective optometer (phoropter) 120 suspending above a table 101 with a column 102 and first and second arms 103 and 104 interposed therebetween, a computer device 130 disposed on the table 101, and an optotype device 140 arranged to be spaced apart from the phoropter 120 by a predetermined distance (distance-sight measurement distance: 3 meters, 5 meters, etc.). Note that an objective optometer (refractometer) may be provided together with the phoropter 120. Further, beside the table 101, a chair (not shown) is provided, and a subject takes an examination while sitting on the chair.
The computer device 130 includes a monitor portion 131 such as a liquid crystal display, and input portions such as a keyboard 132 and a mouse 133 for use in input operations for designating various operations of the optometer 100. On the monitor portion 131, a variety of operation screens, measurement result display screens, and the like are displayed.
Further, the optotype device 140 displays a distance optometry target (chart) C such as a Landolt ring on a presentation window 141, and presents the target C to the subject. The target C presented to the subject is selected by the mouse 133 and the like based on the operation screen displayed on the monitor portion 131 of the computer device 130.
FIG. 12 shows a structure of a front face (face opposite to the optotype device 140) of the phoropter 120. The phoropter 120 includes a right measurement unit 120R for performing a refraction measurement for a right eye to be examined, a left measurement unit 120L for performing a refraction measurement for a left eye to be examined, and a support unit 120A for supporting these measurement units 120R and 120L.
The right measurement unit 120R and the left measurement unit 120L are composed to be left-and-right symmetric. In the drawing, detailed description of the left measurement unit 120L is omitted. Description is made below only of a structure of the right measurement unit 120R (hereinafter, sometimes simply referred to as a “measurement unit 120R”).
The support unit 120A supports the respective measurement units 120R and 120L so that the measurement units 120R and 120L can be individually displaced in a left-and-right direction. On side surfaces of the support unit 120A, PD change knobs 121 for displacing the respective measurement units 120R and 120L to the left and the right are provided. An examiner rotationally operates the PD change knobs 121, and arranges optometric windows 150 of the respective measurement units 120R and 120L immediately in front of the right eye to be examined and the left eye to be examined. Specifically, the PD change knobs 121 are operated to align a width between the left and right optometric windows 150 with the inter-pupil distance (PD) of the subject. The width between the left and right optometric windows 150 (between optical axes of lenses arranged therein) is displayed on a PD display portion 122.
Further, the support unit 120A supports a forehead rest 123 disposed on back sides of the right measurement unit 120R and the left measurement unit 120L. Reference numeral 124 denotes an indicator representing a contact pressure of the forehead of the subject to the forehead rest 123. Further, provided on an upper center portion of the support unit 120A is a near-optometric rod attachment portion 125 onto which a rod for supporting a target for a near-distance test of the eyes to be examined is attached. The near-optometric rod attachment portion 125 is set to be rotatable between a vertically upper direction and a horizontally forward direction, is inclined to the horizontally forward direction to present the near optometric target to the eyes to be examined at the time of the near optometric test, and is received in the vertically upper direction at the time of being unused.
In the measurement unit 120R, various optometric lenses including correction lenses such as a group of spherical lenses for correcting a spherical power of the eye to be examined and a group of cylindrical lenses for correcting a cylindrical power thereof are incorporated. The respective optometric lenses are provided on a turret plate and the like so as to be selectively disposed on the optometric window 150 of the measurement unit 120R. The right eye to be examined peers through the optometric window 150 from the back side of the measurement unit 120R, thereby visually recognizing the target C presented to the optotype device 140.
Description is further made of a structure of the front face of the right measurement unit 120R with reference to FIGS. 13 to 15.
Provided on the front face of the measurement unit 120R are a spherical power changing portion 151 for changing a spherical power (correcting a spherical power) of correcting the eye to be examined, that is, for changing the spherical lens disposed on the optometric window 150, and a spherical power display portion 161 for mechanically displaying the spherical power of the spherical lens disposed on the optometric window 150.
The spherical power changing portion 151 has a structure including a first change knob 151a rotationally operated in order to change the correcting spherical power stepwise by each (±) 0.25 diopters, and a second change knob 151b formed to protrude to a center portion of the first change knob 151a and for changing the correcting spherical power stepwise by each (±) 3 diopters.
The spherical power display portion 161 changes the spherical power displayed thereon in correspondence with rotation of the spherical power changing portion 151. More specifically, when the first change knob 151a is rotated by one step, a numeric value displayed on the spherical value display portion 161 is changed by “(+/−) 0.25” in response to a direction of the rotation. In a similar way, when the second change knob 151b is rotated by one step, a numeric value displayed on the spherical value display portion 161 is changed by “(+/−) 3” in response to a direction of the rotation. Such a corresponding operation of the change and display of the spherical power is performed by an interlocking mechanism in the measurement unit 120R.
Further, provided in the measurement unit 120R is a cylindrical power changing portion 152 for changing the cylindrical power (correcting the cylindrical power) of correcting the eye to be examined, that is, for changing the cylindrical lens disposed on the optometric window 150, and a cylindrical power display portion 162 for mechanically displaying the cylindrical power of the cylindrical lens disposed on the optometric window 150.
When the cylindrical power changing portion 152 is rotated by one step, the correcting cylindrical power is changed by (±) 0.25 diopters in response to a direction of the rotation. When the cylindrical power changing portion 152 is rotated by one step, a numeric value displayed on the cylindrical power display portion 162 is changed by “(+/−) 0.25” in response to the direction of the rotation. This corresponding operation is also performed by the corresponding mechanism in the measurement unit 120R.
Further, a lens support plate 153 rotatable about a shaft 153a is attached onto the front face of the measurement unit 120R. Provided on both ends of the lens support plate 153 are a cross cylinder lens portion 154 for a cross cylinder test, and a rotary prism portion 155 for prism examination, which are for examining astigmatism of the eye to be examined. A cylindrical axis display portion 164 for displaying a cylindrical axis degree in the cross cylinder test is provided around the shaft 153a of the lens support plate 153. Further, an operation knob 153b is formed at one end of the lens support plate 153. The examiner rotates the lens support plate 153 by holding the operation knob 153b, thus making it possible to dispose the cross cylinder portion 154 or the rotary prism portion 155 immediately in front of the optometric window 150.
The cross cylinder lens portion 154 includes a cylindrical lens 154a in a center portion thereof. The cylindrical lens 154a is structured so that a front and back thereof can be switched about, as a center, a rotation axis inclined by 45° with respect to a cylindrical axis thereof. The switching of the front and back of the cylindrical lens 154a is performed by rotating a switch dial 154b. 
Further, the cross cylinder lens portion 154 is structured to be rotatable about an optical axis of the cylindrical lens 154a as a center, thus making it possible to change the cylindrical axis degree of the cylindrical lens 154a. The cylindrical axis degree of the cylindrical lens 154a is displayed on the cylindrical axis display portion 164.
As shown in FIG. 14, the cylindrical axis display portion 164 includes a mechanical structure including a disc-like dial plate 164a in which a scale representing the cylindrical axis degree is written on a peripheral edge portion, and indication marks 164c provided on an edge end portion 164b on the periphery of the dial plate 164a and for indicating the scale on the dial plate 164a. On the scale on the dial plate 164a, the cylindrical axis degrees of 0° to 180° are written twice. The indication marks 164c are provided in a pair at positions opposite to each other with the dial plate 164a interposed therebetween (that is, positions apart from each other by 180°). The indication marks 164c individually indicate scales of the same frequency as that of the dial plate 164a. 
The dial plate 164a is structured so as not to rotate together with the lens support plate 153 or the cross cylinder lens portion 154 even if either thereof is rotated (in the dial plate 164a of FIG. 14, a line of 0° to 180° is always located horizontally). Meanwhile, the edge end portion 164b is structured so as, when the cross cylinder lens portion 154 is rotated, to rotate about the shaft 153a as a center by the same degree as a displacement of the cylindrical axis degree of the cylindrical lens 154a in correspondence with the rotation of the cross cylinder lens portion 154 though not to rotate even if the lens support plate 153 is rotated. In such a way, the indication marks 164c indicate the scales equal to the cylindrical axis degree of the cylindrical lens 154a. Note that the corresponding operation of the rotation of the edge end portion 164b with the rotation of the cross cylinder lens portion 154 is performed by the interlocking mechanism in the measurement unit 120R.
As shown in FIG. 15, the rotary prism portion 155 includes a mechanical structure including a prism portion 155a including two lenses for generating a prism power, a holding portion 155b for holding the two lenses of the prism portion 155a, an indication mark 155c provided on the holding portion 155b, an annular dial plate 155d on which a scale representing the prism power is provided, and a change dial 155e for changing the prism power generated by the prism portion 155a by rotating the respective lenses thereof.
The rotary prism portion 155 is structured so as not to rotate even if the lens support plate 153 is rotated. Further, the dial plate 155d is structured so as not to rotate even if the change dial 155e is rotationally operated. In the dial plate 155d of FIG. 15, a line of “20” to “20” is always located vertically.
The two lenses of the prism portion 155a individually have a prism power of, for example, 10 prism diopters. The lenses concerned are rotated in response to an operation to the change dial 155e, thus making it possible for the prism portion 155a to generate a prism power of 0 to 20 prism diopters. Further, these two lenses are rotated together, thus making it possible to change a prism base direction. On the dial plate 155d, a scale is provided within the range of 0 to 20 prism diopters in response to the prism base direction (of raising and lowering the base).
When the change dial 155e is rotated, the holding portion 155b is rotated together with the lenses of the prism portion 155a (the dial plate 155d is not rotated). At this time, the indication mark 155c on the holding portion 155b is also rotated, and indicates the scale on the dial plate 155d, which represents the prism power generated by the prism portion 155a. 
Further, provided on the front face of the measurement unit 120R is an auxiliary lens switching portion 156 for selectively disposing auxiliary optometric lenses such as various auxiliary lenses in the optometric window 150. Usable as the auxiliary optometric lenses applied in a switching manner by the auxiliary lens switching portion 156 are, for example, a spherical lens, a cylindrical lens, a prism, a polarizing filter, a green filter, a red filter, a Maddox rod, and a pinhole, which are for auxiliary use. Further, reference numeral 157 denotes an indicator for indicating a position of a corneal vertex of the eye to be examined with respect to the optometric window 150.
In the case of using such an optometer including the phoropter for mechanically displaying an examination result, the examiner reads the numeric values displayed on the respective display portions of the phoropter and the scales indicated by the indication marks thereof. In addition, the examiner enters the read values to the computer device 130, or writes down the values concerned on a recording sheet such as a medical chart, thus recording the examination result.
However, in this conventional recording method, the displayed numeric values and the indicated scales are visually read, and accordingly, a reading error, an entering error, and a recording error are sometimes made. If such an artificial error occurs, then a possibility to cause a misdiagnosis owing to erroneous recording contents may increase. In addition, there is a possibility that a necessity of another examination occurs to burden the examiner and the subject. Further, for the examiner who must examine many subjects a day, it is supposed to be heavily burdensome and merciless to be expected to eliminate such errors.
Next, the trial frame is described. Similarly to the phoropter, the trial frame is one for imparting a collecting refractive power to the eyes to be examined, and is used in place of the phoropter. The collecting refractive power is imparted by using trial lenses (examination lenses) with various powers in a switching manner.
FIGS. 16A and 16B show a structure of the trial frame. FIG. 16A shows a structure of a trial frame 200, and FIG. 16B shows a structure of a trial lens 202 attached into lens holding frames 201R and 201L of the trial frame 200.
The trial lens 202 includes an annular frame 202a, a lens 202b held by the annular frame 202a, a protrusion 202c protruded integrally with an outer circumferential surface of the annular frame 202a toward the outside in the radius direction, and a tab 202d provided on a tip of the protrusion 202c. The lens 202b has a predetermined refractive power (such as spherical power and cylindrical power), and on the tab 202d, the refractive power of the lens 202b concerned is written. In an optometry using the trial frame, a large number of trial lenses 202 having various refractive powers are used.
The trial frame 200 includes a structure for imparting a correcting spherical power and correcting cylindrical power individually to the right eye to be examined and the left eye to be examined. The trial frame 200 includes left and right annular plate portions 200L and 200R as holding frame attachment bases, a bridge 200B also serving as a nosepiece, which couples the annular plate portions 200L and 200R continuously and integrally with each other, attachment plate portions 203L and 203R provided integrally with outer edge portions of the annular plate portions 200L and 200R, and temples 204L and 204R attached to these attachment plate portions 203L and 203R.
The lens holding frames 201L and 201R are held so as to be rotatable in the circumferential direction in the annular plate portions 200L and 200R. Onto the annular plate portions 200L and 200R, operation knobs 205L and 205R for rotationally operating the lens holding frames 201L and 201R are attached below the attachment plate portions 203L and 203R. By rotating the operation knobs 205L and 205R in directions of arrows B1 and B2, respectively, the lens holding frames 201L and 201R rotate in directions of arrows C1 and C2, respectively.
Further, scales 206L and 206R are formed along the circumferential direction on front faces of the annular plate portions 200L and 200R. These scales 206L and 206R represent cylindrical axis degrees of the trial lenses for imparting the correcting cylindrical powers. When the trial lens 202 is one for correcting the cylindrical power, the direction of the tab 202d thereof, that is, a position of each of the scales 206L and 206R, which is indicated by the protrusion 202c, represents the cylindrical axis degree at that time.
Provided on front faces of the lens holding frames 201L and 201R are lens receiving portions 207L and 207R in which plural grooves for receiving the trial lenses 202 are formed, and plate springs 208L and 208R for pressing the trial lenses 202 against the lens receiving portions 207L and 207R and holding the trial lenses 202 therein.
Also in an optometer using the trial frame as described above, it is necessary for the examiner to visually read the numeric values and the scales, which are mechanically displayed on the trial frame and the trial lenses, to enter the numeric values and the scales to the computer device 130, and to write down the values and the scales in the recording sheet. Accordingly, as in the case of the phoropter, the reading error, the entering error, and the recording error are sometimes made.